* doc/bison.texinfo (Calc++ Scanner): The flex behavior is an

[bison.git] / data / glr.cc

m4_divert(-1)                                                       -*- C -*-

# C++ GLR skeleton for Bison
# Copyright (C) 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301  USA


# This skeleton produces a C++ class that encapsulates a C glr parser.
# This is in order to reduce the maintenance burden.  The glr.c
# skeleton is clean and pure enough so that there are no real
# problems.  The C++ interface is the same as that of lalr1.cc.  In
# fact, glr.c can replace yacc.c without the user noticing any
# difference, and similarly for glr.cc replacing lalr1.cc.
#
# The passing of parse-params
#
#   The additional arguments are stored as members of the parser
#   object, yyparser.  The C routines need to carry yyparser
#   throughout the C parser; that easy: just let yyparser become an
#   additional parse-param.  But because the C++ skeleton needs to
#   know the "real" original parse-param, we save them
#   (b4_parse_param_orig).  Note that b4_parse_param is overquoted
#   (and c.m4 strips one level of quotes).  This is a PITA, and
#   explains why there are so many levels of quotes.
#
# The locations
#
#   We use location.cc just like lalr1.cc, but because glr.c stores
#   the locations in a (C++) union, the position and location classes
#   must not have a constructor.  Therefore, contrary to lalr1.cc, we
#   must not define "b4_location_constructors".  As a consequence the
#   user must initialize the first positions (in particular the
#   filename member).


# We require a pure interface using locations.
m4_define([b4_location_flag], [1])
m4_define([b4_pure],          [1])

m4_include(b4_pkgdatadir/[c++.m4])
m4_include(b4_pkgdatadir/[location.cc])


# Save the parse parameters.
m4_define([b4_parse_param_orig], m4_defn([b4_parse_param]))


# b4_yy_symbol_print_generate
# ---------------------------
# Bypass the default implementation to generate the "yy_symbol_print"
# and "yy_symbol_value_print" functions.
m4_define([b4_yy_symbol_print_generate],
[[
/*--------------------.
| Print this symbol.  |
`--------------------*/

]b4_c_ansi_function_def([yy_symbol_print],
    [static void],
    [[FILE *],               []],
    [[int yytype],           [yytype]],
    [[const b4_namespace::b4_parser_class_name::semantic_type *yyvaluep],
			     [yyvaluep]],
    [[const b4_namespace::b4_parser_class_name::location_type *yylocationp],
			     [yylocationp]],
    b4_parse_param)[
{
]b4_parse_param_use[]dnl
[  yyparser.yy_symbol_print_ (yytype, yyvaluep]b4_location_if([, yylocationp])[);
}
]])


# Declare yyerror.
m4_append([b4_post_prologue],
[/* Line __line__ of glr.cc.  */
b4_syncline([@oline@], [@ofile@])

b4_c_ansi_function_decl([yyerror],
    [static void],
    [[b4_namespace::b4_parser_class_name::location_type *yylocationp], [yylocationp]],
    b4_parse_param,
    [[const char* msg], [msg]])])


# Define yyerror.
m4_append([b4_epilogue],
[/* Line __line__ of glr.cc.  */
b4_syncline([@oline@], [@ofile@])[
/*------------------.
| Report an error.  |
`------------------*/

]b4_c_ansi_function_def([yyerror],
    [static void],
    [[b4_namespace::b4_parser_class_name::location_type *yylocationp], [yylocationp]],
    b4_parse_param,
    [[const char* msg], [msg]])[
{
]b4_parse_param_use[]dnl
[  yyparser.error (*yylocationp, msg);
}


namespace ]b4_namespace[
{
]dnl In this section, the parse param are the original parse_params.
m4_pushdef([b4_parse_param], m4_defn([b4_parse_param_orig]))dnl
[  /// Build a parser object.
  ]b4_parser_class_name::b4_parser_class_name[ (]b4_parse_param_decl[)
    : yycdebug_ (&std::cerr)]b4_parse_param_cons[
  {
  }

  ]b4_parser_class_name::~b4_parser_class_name[ ()
  {
  }

  int
  ]b4_parser_class_name[::parse ()
  {
    return ::yyparse (*this]b4_user_args[);
  }

#if YYDEBUG
  /*--------------------.
  | Print this symbol.  |
  `--------------------*/

  inline void
  ]b4_parser_class_name[::yy_symbol_value_print_ (int yytype,
			   const semantic_type* yyvaluep, const location_type* yylocationp)
  {
    /* Pacify ``unused variable'' warnings.  */
    YYUSE (yyvaluep);
    YYUSE (yylocationp);
    switch (yytype)
      {
  ]m4_map([b4_symbol_actions], m4_defn([b4_symbol_printers]))dnl
[        default:
	  break;
      }
  }


  void
  ]b4_parser_class_name[::yy_symbol_print_ (int yytype,
			   const semantic_type* yyvaluep, const location_type* yylocationp)
  {
    *yycdebug_ << (yytype < YYNTOKENS ? "token" : "nterm")
	       << ' ' << yytname[yytype] << " ("
	       << *yylocationp << ": ";
    yy_symbol_value_print_ (yytype, yyvaluep, yylocationp);
    *yycdebug_ << ')';
  }

  std::ostream&
  ]b4_parser_class_name[::debug_stream () const
  {
    return *yycdebug_;
  }

  void
  ]b4_parser_class_name[::set_debug_stream (std::ostream& o)
  {
    yycdebug_ = &o;
  }


  ]b4_parser_class_name[::debug_level_type
  ]b4_parser_class_name[::debug_level () const
  {
    return ::yydebug;
  }

  void
  ]b4_parser_class_name[::set_debug_level (debug_level_type l)
  {
    ::yydebug = l;
  }

#endif /* ! YYDEBUG */
]m4_popdef([b4_parse_param])dnl
[} // namespace ]b4_namespace[

]])


# Let glr.c believe that the user arguments include the parser itself.
m4_ifset([b4_parse_param],
[m4_pushdef([b4_parse_param],
	    m4_dquote([[[b4_namespace::b4_parser_class_name& yyparser], [[yyparser]]],]
m4_defn([b4_parse_param])))],
[m4_pushdef([b4_parse_param],
	    [[[[b4_namespace::b4_parser_class_name& yyparser], [[yyparser]]]]])
])
m4_include(b4_pkgdatadir/[glr.c])
m4_popdef([b4_parse_param])


@output @output_header_name@
b4_copyright([Skeleton interface for Bison GLR parsers in C++],
  [2002, 2003, 2004, 2005, 2006])
[
/* As a special exception, you may create a larger work that contains
   part or all of the Bison parser skeleton and distribute that work
   under terms of your choice, so long as that work isn't itself a
   parser generator using the skeleton or a modified version thereof
   as a parser skeleton.  Alternatively, if you modify or redistribute
   the parser skeleton itself, you may (at your option) remove this
   special exception, which will cause the skeleton and the resulting
   Bison output files to be licensed under the GNU General Public
   License without this special exception.

   This special exception was added by the Free Software Foundation in
   version 2.2 of Bison.  */

/* C++ GLR parser skeleton written by Akim Demaille.  */

#ifndef PARSER_HEADER_H
# define PARSER_HEADER_H

#include <string>
#include <iostream>

/* Using locations.  */
#define YYLSP_NEEDED ]b4_locations_flag[

namespace ]b4_namespace[
{
  class position;
  class location;
}

/* Copy the first part of user declarations.  */
]b4_pre_prologue[

]/* Line __line__ of glr.cc.  */
b4_syncline([@oline@], [@ofile@])[

#include "location.hh"

/* Enabling traces.  */
#ifndef YYDEBUG
# define YYDEBUG ]b4_debug[
#endif

/* Enabling verbose error messages.  */
#ifdef YYERROR_VERBOSE
# undef YYERROR_VERBOSE
# define YYERROR_VERBOSE 1
#else
# define YYERROR_VERBOSE ]b4_error_verbose[
#endif

/* Enabling the token table.  */
#ifndef YYTOKEN_TABLE
# define YYTOKEN_TABLE ]b4_token_table[
#endif

/* YYLLOC_DEFAULT -- Set CURRENT to span from RHS[1] to RHS[N].
   If N is 0, then set CURRENT to the empty location which ends
   the previous symbol: RHS[0] (always defined).  */

#ifndef YYLLOC_DEFAULT
# define YYLLOC_DEFAULT(Current, Rhs, N)				\
    do									\
      if (N)								\
	{								\
	  (Current).begin  = YYRHSLOC (Rhs, 1).begin;			\
	  (Current).end    = YYRHSLOC (Rhs, N).end;			\
	}								\
      else								\
	{								\
	  (Current).begin = (Current).end = YYRHSLOC (Rhs, 0).end;	\
	}								\
    while (/*CONSTCOND*/ 0)
#endif

namespace ]b4_namespace[
{
  /// A Bison parser.
  class ]b4_parser_class_name[
  {
  public:
    /// Symbol semantic values.
#ifndef YYSTYPE
]m4_ifdef([b4_stype],
[    union semantic_type
b4_stype
/* Line __line__ of lalr1.cc.  */
b4_syncline([@oline@], [@ofile@])
	;],
[    typedef int semantic_type;])[
#else
    typedef YYSTYPE semantic_type;
#endif
    /// Symbol locations.
    typedef ]b4_location_type[ location_type;
    /// Tokens.
    struct token
    {
      ]b4_token_enums(b4_tokens)[
    };
    /// Token type.
    typedef token::yytokentype token_type;

    /// Build a parser object.
    ]b4_parser_class_name[ (]b4_parse_param_decl[);
    virtual ~]b4_parser_class_name[ ();

    /// Parse.
    /// \returns  0 iff parsing succeeded.
    virtual int parse ();

    /// The current debugging stream.
    std::ostream& debug_stream () const;
    /// Set the current debugging stream.
    void set_debug_stream (std::ostream &);

    /// Type for debugging levels.
    typedef int debug_level_type;
    /// The current debugging level.
    debug_level_type debug_level () const;
    /// Set the current debugging level.
    void set_debug_level (debug_level_type l);

  private:

  public:
    /// Report a syntax error.
    /// \param loc    where the syntax error is found.
    /// \param msg    a description of the syntax error.
    virtual void error (const location_type& loc, const std::string& msg);
  private:

#if YYDEBUG
  public:
    /// \brief Report a symbol value on the debug stream.
    /// \param yytype       The token type.
    /// \param yyvaluep     Its semantic value.
    /// \param yylocationp  Its location.
    virtual void yy_symbol_value_print_ (int yytype,
					 const semantic_type* yyvaluep,
					 const location_type* yylocationp);
    /// \brief Report a symbol on the debug stream.
    /// \param yytype       The token type.
    /// \param yyvaluep     Its semantic value.
    /// \param yylocationp  Its location.
    virtual void yy_symbol_print_ (int yytype,
				   const semantic_type* yyvaluep,
				   const location_type* yylocationp);
  private:
#endif /* ! YYDEBUG */


    /// \brief Reclaim the memory associated to a symbol.
    /// \param yymsg        Why this token is reclaimed.
    /// \param yytype       The symbol type.
    /// \param yyvaluep     Its semantic value.
    /// \param yylocationp  Its location.
    inline void yydestruct_ (const char* yymsg,
			     int yytype,
			     semantic_type* yyvaluep,
			     location_type* yylocationp);

    /* Debugging.  */
    std::ostream* yycdebug_;
]b4_parse_param_vars[
  };

]dnl Redirections for glr.c.
m4_ifset([b4_global_tokens_and_yystype],
[b4_token_defines(b4_tokens)])
[
#ifndef YYSTYPE
# define YYSTYPE ]b4_namespace[::]b4_parser_class_name[::semantic_type
#endif
#ifndef YYLTYPE
# define YYLTYPE ]b4_namespace[::]b4_parser_class_name[::location_type
#endif

}

#endif /* ! defined PARSER_HEADER_H */]